Oddy test

As one of the people who did the early development work on the
so-called Oddy test,  I would like to reply to David Harvey's
comments (Conservation DistList Instance: 14:50 Wednesday, March 28,
2001).

First as an earlier correspondent said the test is a quick and dirty
test.  It is only meant to give a pass fail result. Yes a material
is safe to use because it does not corrode the metal sample or no it
is not safe to use because it does corrode the sample.  The test is
a simple derivative of a standard corrosion testing method. It is
not true that there is not  a standard test. After an exhaustive
interlaboratory comparison my Conservation Research colleagues Lorna
Green and David Thickett published a standard procedure, Testing
materials for the storage and display of artefacts--a revised
methodology, Studies in Conservation, 40, (3), 145-52.  There have
been several other methods of doing this test, or using completely
different methodology to evaluate materials published by other
workers.  We use the Green and Thickett method and the only problems
encountered have been those reported earlier in this list by my
colleague Laurianne Robinet.

The problem of poor laboratory working practice is not unique to
conservators, and it is a problem which can be countered by proper
training of staff and carefully following the written method.  The
idea that a material cannot be accepted for use on the basis of the
test is rather scary.  We do not experience false positive tests,
but we probably do fail materials which would be safe to use in the
construction of showcases, or storage units.  This test is not
suitable for the evaluation of conservation materials for which a
more complex scientific methodology is needed.  It is sometimes
useful to know if a conservation material will cause damage to
object substrates, but we would never ever recommend a material for
use in the conservation of objects on the basis of the test.

I agree that standard testing is needed in Conservation, and tried
for many years during the 80s and early 90s with Yvonne Shashoua to
get others interested in this.  At that time it seemed that the BM
scientists were the only group routinely testing conservation
materials.  If there is a move to produce standard reproducible
tests we are certainly interested.

Susan Bradley
Head of Conservation Research Group
Department of Conservation
British Museum
London WC1B 3DG
+44 20 7323 8679
Fax: +44 20 7323-8636


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                  Conservation DistList Instance 14:51
                  Distributed: Tuesday, April 3, 2001
                       Message Id: cdl-14-51-004
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